The present project deals with defining the pathways of bile acid synthesis in patients with and without diseases of their liver. Various inborn errors of bile acid metabolism have been identified and others will be searched for and correlations will be made between the metabolic defects and the degree and type of liver disease the patients have. Factors controlling and regulating bile acid synthesis in man will be studied. The rate controlling enzyme in bile acid synthesis is 7 alpha-hydroxylase and how this enzyme is influenced will be studied during the coming year.